Waveguide switches are used in a broad range of applications with two main functions: They are used either to route signals for connecting the appropriate network elements or to provide redundancy schemes. Many spacecraft systems incorporate sophisticated switch matrices in order to increase the system reliability. They provide redundancy connections which are activated to bypass failing devices either automatically or by ground terminal commands.
The switching networks are relatively easy to realize at low frequencies and at low signal power levels. The switches for low power applications are typically implemented using coaxial technology. Waveguide switches, on the other hand, are preferred in high frequency and for high power applications. However, when several ports are involved, signal routing in waveguide switches (such as changes in the propagation direction or signal crossovers) are more difficult to implement limiting the use of conventional waveguide switches to C and R switches. At the same time, since mass and volume must be kept to a minimum in many applications such as satellite systems, there are demands for new improved compact switch designs with more advanced functionality.
Several waveguide switches have been proposed for RF and microwave systems. Many of them are based on the rotation of a junction or waveguide section inside the main body of the device. They are either manually operated or controlled by electromechanical systems. In this last case, they have an internal mechanical linkage with a motor or a rotary solenoid for automated actuation (e.g., U.S. Pat. No. 4,967,170).
Ridge waveguides were combined with MEMS switches for the realization of simple switch configurations such as SPST, SP2T and C-switches [U.S. Pat. No. 7,292,125]. The structures proposed in prior art, such as those in U.S. Pat. Nos. 4,967,170 and 7,292,125, cannot be easily employed in the realization of waveguide T-switches or switches with relatively large number of ports such as SP4T or SP6T switches. The availability of such waveguide switches makes it possible to realize highly advanced compact switch matrices with fewer elements.